Nature's Bounty lmmune 24 Hour + nourishes your immune systemwith 1000 mg of Ester-C, the only Vitamin C that provides 24-hourimmune support while lasting up to two times longer than reqularVitamin C. Backed by over twenty years of clinical research, thisunique, highly bioavailable form of Vitamin C stavs in white blood cellsonger than reqular vitamin C, supporting immune function and upperrespiratory health f lt additionally contains Vitamin D, Vitamin A andZinc for extra immune plus antioxidant support. Elderberry and chinacea plus 9 essential nutrients also help keep you healthy.